I've actually seen public schools with stricter dress codes. And those who are "expressive" find ways to dress crazy while staying within the rules and nothing can be done about it because they aren't breaking any rules.

The school my parents teach at (public school) they have a very strict dress code. On top of your list add
boys can't wear earings,
men must be clean shaven,
sideburns must not be any longer than the bottom of your ear, hair must be above your shirt collar for men
Shorts can only be worn on Friday and both shorts and skirts can be no shorter than 5 inches above the knee
A female can have no more then 2 piercings per ear and no facial peircings for males or females
Shirts with a tail must be tucked in
and my personal favorite men are not allowed to wear womens clothing.